1. Field of the Invention
The present invention generally relates to a light module and a display having the same, and particularly to a backlight module and a liquid crystal display (LCD) having the same.
2. Description of Related Art
Generally, a backlight module provides a plane light source for an LCD panel for displaying. Conventional backlight modules are classified into two types, direct type backlight module, and side type backlight module. Typically, direct type backlight modules can provide surface sources brighter than side type backlight module. Therefore, direct type backlight modules are more often adopted when higher brightness of the light sources is required. Conventional direct type backlight modules are illustrated as below for reference.
FIG. 1 is a cross-sectional view of a conventional direct type backlight module. Referring to FIG. 1, the conventional direct backlight module 100 includes a frame 110, a plurality of light emitting diodes (LED) 130, and a diffusing plate 140. The frame 110 includes a bottom plate112. The LEDs 130 are disposed on the bottom plate 112, and the diffusing plate 140 is disposed in the frame 110 and over the LEDs 130. The LEDs 130 are adapted for emitting red light, green light, and blue light, respectively, which can be evenly mixed into white light and thereafter pass through the diffusing plate, thus providing a white light source for the LCD.
However, the operation temperature of the LEDs 130 will increase when the LEDs 130 are used for a long time. Thereby, the light emitting efficiencies of the LEDs 130 gradually deteriorated, and the light emitting efficiencies of the LEDs 130 which emitting different color lights deteriorated with different rates. Therefore, the LCD exhibits an unstable image quality, for in capable of maintaining the original chroma and brightness. As a solution, at least one photo sensor chip 150 is often employed for sensing the chroma and the brightness thereof. The photo sensor chip 150 transmits signals generated thereby corresponding the obtained chroma and/or brightness to a driving circuit (not shown) for adjusting and compensating the light emitted from the LEDs 130.
The photo sensor chip 150 is a flat chip, which front side is often the primary side to be illuminated. In order to sense the chroma and the brightness of the light correctly, the photo sensor chips 150 should be distributed in areas where the light of different colors are most evenly mixed, mostly in front of the diffusing plate 140 as shown in FIG. 1. According to such a design, the photo sensor chip 150 can sense the most evenly mixed light so as to accurately evaluate the light provided by the backlight module 100, and consult the driving circuit to properly adjust and compensate.
However, unfortunately, the photo sensor chip 150 somehow blocks the light provided by the backlight module 100, thus affects the light output efficiency of the backlight module 100.